1. Field of the Invention
The apparatus of the present invention relates to protection of valve stems. More particularly, the apparatus of the present invention relates to a protective cover for manual operated valve stems.
2. General Background
In any environment which utilizes the various types of large industrial valves which incorporate basically a stem and a manual hand wheel for removing the valving apparatus, in most cases these valve stems are threaded and often times are exposed to various types of corrosive environments, including dust, dirt, chemicals, or other corrosive material that may enter threads of the valve stem, and the threaded nut within the manual hand wheel, thus causing the valve stem and nut to become corroded, often times resulting in a jammed valved apparatus or, in some cases, breaking of the valve stem itself.
Several patents disclose the protection of valve stems, which include the following:
U.S. Pat. No. 2,578,630 discloses a valve shank protector with the use of a threaded cap which is mounted in an inverted position on the top of a hand wheel beneath the lock nut. The protector is then threaded into the threads which match those threads at the cap.
U.S. Pat. No. 2,890.710 issued to J. H. Hartman, entitled "Protector" discloses a metal dome which would interlock with veinette slots to a lower flange with an upper extention of the apparatus covering the valve stem itself as a protector.
U.S. Pat. No. 2,816,566 issued to C. C. Warren, entitled "Shield or protective for a valve stem" the disclosed and upper externally threaded sleeve received thereupon a threaded cap. The cap can be removed for filling the sleeve with a lubricant as the case may be.